1. Field of the Invention
This invention relates to bacon slicing, and, more particularly, relates to an apparatus and method for maintaining the orientation of the end-piece of a slab of bacon as the slab passes through a continuous bacon slicer.
2. Description of the Prior Art
In the past, mechanical bacon slicers were developed to produce the precisely packaged drafts commonly found in the retail market. Initially, bacon slicers employed a reciprocating ram to feed a slab of bacon into the path of a slicing blade in slice-thickness steps. The ram positively gripped one end of the slab. The blade cut slices from the opposite end. When the ram reached the travel limit imposed by the blade, the ram was withdrawn, the end-piece was removed, a fresh slab was loaded into the slicer, and the process was repeated. While the ram-type slicer was relatively slow, it allowed nearly the entire slab to be fed through the blade. The positive grip on the end of the slab maintained the proper slicing orientation throughout the full length, producing a good slice-yield for each slab.
Subsequently, in an effort to speed-up the slicing process, continuous-type slicers were developed. A continuously advancing drive gripped the top and bottom of the slab, and continuously fed the slab forward into the path of the rotating blade. The relative timing between the feed rate of the drive and the rotational speed of the blade determined the slice thickness. The successive slices dropped onto a scale. When the scale indicated that the load of slices had reached the desired package weight, the advancing drive paused to permit removal of the accumulated slices from the scale.
As each slab neared the completion of its pass into the path of the slicing blade, the remaining end-piece traveled beyond contact with the drive. The following slab, however, continued to push the preceding end-piece into the blade path.
This gave rise to another problem; as the blade sliced through the end-piece, it tended to pull the remainder forward in an irregular manner. Once the end-piece had been dis-oriented, the succeding pass of the slicing blade produced a correspondingly irregular slice. As a result, continuous-type bacon slicers tended to produce an inordinate proportion of "ends and pieces", which has a substantially lower market value than did regular bacon slices. Since domestic bacon production exceeded millions of pounds per year, such a productivity loss had serious economic consequences.
In a series of attempts to control the attitude of the end-pieces as they passed through the slicer, a number of devices were introduced. One attempt to solve this problem is presented in U.S. Pat. No. 4,329,900, issued to Cashin Systems Corporation. That device employed a "hold down device", which included a single "rotatable gripper", or gripping driver, located next to the slicing blade. The gripper was mounted on a pivotally supported arm. The gripper started and stopped in synchronization with the drive for the bacon slab. The gripper helped to precisely feed the slab into the path of the slicing blade. Since the gripper advanced the slab slowly, at least in comparison to the speed of the blade, the gripper also tended to hold the slab stationary during the actual slicing operation. The loaded gripper thus held the slab back against the pull of the blade as the slicing operation took place.
Problems, however, still persisted; since the slabs of bacon varied in thickness, the pivotally supported arm had to swing the gripper up or down to accommodate the thickness of a particular slab. As the gripping driver pivoted about the radius of the arm, it moved from its position next to the plane of the slicing blade. The gripping driver moved farther away for a thinner slab. As a direct result, when thinner slabs were sliced an undesirably large proportion of "ends and pieces" were still produced.
A need continued to exist for an apparatus or method to more consistantly control the attitude of the end of each slab passing through a continuous-type bacon slicer, regardless of the relative thickness of any individual slab.
Another persisting problem arose due to the inability of the devices of the prior art to accomodate the thickness variations across the lateral dimension of a slab of bacon. The "lean" portion of the slab, taken from the belly-region of the hog, was generally thicker than the "fatback" portion of the slab, taken from the back-region of the hog. The "side" of the hog carcass was cured to produce a bacon slab. Before slicing, the cured slab was generally trimmed by removing a slice of the "backstrap" fat from the fatback portion.
As a result of the uneven thickness of a typical bacon slab, the singular grippers employed in the known devices of the prior art offered a degree of support for the lean portion of the slab, but tended to permit the blade to preferentially pull the fatback portion of the slab further into the path of the blade. Again, the result was often an inordinate proportion of irregular slices, which were not acceptable for inclusion in a display-case package.
A need continued to exist for an apparatus or method to control the attitude and forward motion of the full width of the face of a slab of bacon, as that face approached and encountered the slicing plane of a continuous-type bacon slicer.
Another shortcoming found in the grippers employed on the continuous bacon slicers in the past was a tendency of the teeth employed on the surface of the gripper to squeeze or propel the trailing end of a slab of bacon into the path of the slicing blade.
A need continued to exist for a tooth design for a gripping driver employed in a continuous-type bacon slicer, which tooth was specifically arranged to resist, or at least not contribute to, the forward progress of a trailing end of a slab, even when the gripper was loaded downward against the product.
A further problem persisting with the gripping driver devices found in the prior art was an inability to receive the first in a series of slabs of bacon, without manual assistance to aid in appropriately positioning the gripper. The problem arose because, when lowered to rest on the anvil of the continuous-type slicer, the gripper was also positioned so that the generally vertical leading surface of the first slab of bacon tended to frontally strike the gripper, thereby often resulting in a jam because the gripper was unable to ride onto the upper surface of the slab without manual assistance.
A need continued to exist for an apparatus or method to automatically shift a gripper, mounted adjacent to the slicing plane of a continuous-type bacon slicer, into a gripping engagement with the upper surface of an initial bacon slab, without requiring manual assistance.